Band saw machines generally comprise a continuous flexible metal blade that is trained around a pair of vertically stacked wheels so that the blade may perform cutting operations when the wheels are driven. The wheels may be fixed in a single position, or they may be rotatable to facilitate angular cuts. In either case, band saw machines typically have a work table disposed within the path of the band saw blade to stabilize and position the workpiece for cutting. By necessity, the work tables must have an aperture to permit the band saw blade to travel through the plane of the work table. This aperture is generally much larger than the blade in order to accommodate different blade sizes or to permit rotation of the wheels and blade. For this reason, a slotted throat plate insert is usually placed within the work table aperture to cover the void.
During operation of the band saw machine, the flexible metal blade tends to move in a side to side lateral motion. Lateral motion is undesirable because it reduces the accuracy of the cut and it may cause the blade teeth to strike the workpiece at an angle which scars the workpiece or damages the teeth. If lateral motion is unchecked, the blade may also experience noisy or even catastrophic vibration. In order to minimize lateral motion and vibration, band saws generally have blade guides to restrict movement of the band saw blade. Each blade guide typically comprises a pair of opposed members positioned on either side of the band saw blade a distance away from the work table. In the prior art, one blade guide is typically positioned above the work table and another is positioned below the work table. However, because of the respective distances between the blade guides and the workpiece, lateral blade movement continues to create difficulties in precise machine operations. Specifically, there is a greater tendency for lateral blade movement as the distance between the workpiece and the respective blade guides is increased. Unfortunately, the lower blade guide is generally positioned below the worktable and significantly distant from the workpiece resting thereon. Moreover, band saw machines having a rotatable wheel assembly or a tiltable work table typically position the lower blade guide further from the work table to allow such rotation.
In view of the above considerations, a primary object of the present invention is to provide a blade guide which can be positioned within the plane of the work table in close proximity to the workpiece to effectively restrict lateral motion of the band saw blade. Another object of the invention is to provide a blade guide which is an integral component of a throat plate that is positionable within the work table. Yet another object of the invention is to provide a blade guide having adjustable opposed guide blocks. These and other objects of the present invention will become apparent throughout the description thereof which now follows.